Sorry if this thread was there already. A quick search didn't show up.
I had a hick up with my Leblond lathe. The other day, I turned it on, and it stopped working. The speed change didn't work. Sometimes, it doesn't even turn on. The speed is wrong. Loud noise. Contactor popped. All sort of problems. I thought it could be multiple problems. I recalled vaguely that the noise appears to be louder lately when I ran it. But my memory wasn't that solid on this.
I searched and searched on Leblond, especially about the servo issue. I couldn't find much, although I thought I read it before about a fix. There are fixes out there such as switching to manual speed control, partially switching over VFD and keeping the servo for larger gear change, and replace some cracked plastic dial.
There wasn't much video or info of disassembly.
So I took off the top, then took some courage to remove the speed change assembly on top. It's only 4 bolts. There are 3 linkages below. 2 for the changing forks and 1 for connecting with the front dial knob, which is also a fork type. So they just slide out easily.
I checked the gears that I can see and they look good, which is a good sign. At worse, I may just go with VFD route.
I partially disassembled the hydraulic spool valve speed change unit, and here's what I found:
It is 2 metal parts sandwiching plastic fluid routing parts. The metal parts are the two hydraulic cylinders actuating the changing fork.
The bolts holding them together are very loose (not falling apart loose, just much looser than finger wrench tight).
There are 4 plastic pieces. Two rigid piece on top and bottom. The middle is sliding with the control of the speed dial knob on the front. So when you change the speed on the dial, it re-route the hydraulic spool valve. But that means the pump doesn't run, or doesn't provide enough pressure to change it while the lathe is running. The pump would work and move the hydraulic actuators if it detects a 0 speed and also the electronic wiring from the front dial signal a change from previous value.
A 4th plastic piece is a round "gear" rotating along with the fork from the front speed dial. That round piece provides at least 3 functions: 1. Provides min and max dial position, 2. Drive the middle piece to change to linear motion, allowing various hole patterns to route the hydraulic oil. 3, it provides feedback to the front dial of "step/quantize" selection. So the front dial is not a continuous selector (which makes sense with gear change).
I was able to sand down 1 metal piece to make it flat again (from various light ridges). The other side appears to have many spin pin that I can't remove, so I didn't sand it down. Since I didn't remove the hydraulic pump actuator, my worry while doing that was contamination. So I always hold it with holes pointing down, wiped, clean carefully.
The plastic appears to be ok. I put them back, torque a bit harder. That didn't work. It's too hard to slide. So I had to lessen the bolts. At the end, it's still tighter, but not very tight.
That did reduce the "step" feedback greatly on the front dial, which is a concern for me. When I tested it with the top open, and only doing speed change, not rotating spindle, there are 4 ways that oil can spray out and can give an oil shower. Front, back, left and right. The left and right only happens exclusively, depending high or low gear selection ( I think below or above 300 rpm, not remember exactly). So that is helpful, since I can just block it up with a towel and one hand.
The front and back is not that bad, but can also be helped with a towel. But some how my memory tell me one case it did it both left right, and I put a towel on one end while block the other, but not 100% sure about this.
Another concern I have is tighten it would eventually break the round plastic part.
I also cleaned up the contacts of the 0 speed sensor. Increased the fluid pressure on the back electric panel a bit. I didn't hook up a pressure gauge to check. I think it should be between 200 and 250 psi (or 300psi?) as spec.
The lathe runs much smoother and no electrical issue. I noticed before the reason for the noise was that the lathe was stuck in the beginning running slow speed (even with high speed settings). It starts slow, growling, then kicks to higher speed and smooth.
Now, that actually also happens, but mostly gone for lower speed range. For higher speed, the slow period various, with highest 1200 rpm, it may take 2 or 3 seconds.
Can someone please tell me if this is normal? My rotary converter has somewhat balanced voltages among 3 branches, and a little off when not powering a machine (when not powering a machine, I recall it's something 122v, 132v and 138v).
Another issue I have is somehow the middle "B" selector of the thread cutting dial range is very hard to engage. The dial is broken, so maybe, just maybe it's that, but I just can't even feel anything "engaged" when I move it to the middle. After a very long time, I ended up get it to engaged and produce correct ratio.
When not engaged correctly, it either doesn't turn the screw rod, run at the higher or lower settings. When it runs, no noisy sound, so I hope that is good.
I hope there is some guide removing this assembly, since I have some oil leak on this part. My fault when I transport the late. The handle pointed down. So it was pressed against something (even when I put a 2x4 below), maybe when the 2x4 was off. But it broken. That also puts pressure on the metal shaft and damaged the seal.
Another thing I have been doing lately was getting my horizontal mill to a better condition. The left horizontal table's dial never work (it has a square end, maybe for using a wrench or connecting a power feed). I took it out and a spring pin between the shaft and the gear broken off. So I will replace it. I also found the bronze bushing wore out. I made another one for that.
The main cause (I think) was because the cast iron casing wasn't working correctly somehow. The cap wasn't in all flush. Deep inside there were some uneven surfaces and grooves. I ended up making the square shaft turn smoothly by using rotary tool to cut out those grooves, then use sand paper wrapped around a large socket to smooth the inside out (yes, very low precision, versus cutting it via a mill). It works smoothly now.
I still need to replace a broken "canvas" in the back of the Z-table protecting the chips falling down onto the screw rod. Anyone have any suggestion? I am thinking about using a piece of leather, like a cut out from an old leather couch or a welder apron. What material would best suit for this? I think it may needs to have some "folding" pattern so it can fold into a Z shape when collapsed.
Sorry for the long post, whiny post
I had a hick up with my Leblond lathe. The other day, I turned it on, and it stopped working. The speed change didn't work. Sometimes, it doesn't even turn on. The speed is wrong. Loud noise. Contactor popped. All sort of problems. I thought it could be multiple problems. I recalled vaguely that the noise appears to be louder lately when I ran it. But my memory wasn't that solid on this.
I searched and searched on Leblond, especially about the servo issue. I couldn't find much, although I thought I read it before about a fix. There are fixes out there such as switching to manual speed control, partially switching over VFD and keeping the servo for larger gear change, and replace some cracked plastic dial.
There wasn't much video or info of disassembly.
So I took off the top, then took some courage to remove the speed change assembly on top. It's only 4 bolts. There are 3 linkages below. 2 for the changing forks and 1 for connecting with the front dial knob, which is also a fork type. So they just slide out easily.
I checked the gears that I can see and they look good, which is a good sign. At worse, I may just go with VFD route.
I partially disassembled the hydraulic spool valve speed change unit, and here's what I found:
It is 2 metal parts sandwiching plastic fluid routing parts. The metal parts are the two hydraulic cylinders actuating the changing fork.
The bolts holding them together are very loose (not falling apart loose, just much looser than finger wrench tight).
There are 4 plastic pieces. Two rigid piece on top and bottom. The middle is sliding with the control of the speed dial knob on the front. So when you change the speed on the dial, it re-route the hydraulic spool valve. But that means the pump doesn't run, or doesn't provide enough pressure to change it while the lathe is running. The pump would work and move the hydraulic actuators if it detects a 0 speed and also the electronic wiring from the front dial signal a change from previous value.
A 4th plastic piece is a round "gear" rotating along with the fork from the front speed dial. That round piece provides at least 3 functions: 1. Provides min and max dial position, 2. Drive the middle piece to change to linear motion, allowing various hole patterns to route the hydraulic oil. 3, it provides feedback to the front dial of "step/quantize" selection. So the front dial is not a continuous selector (which makes sense with gear change).
I was able to sand down 1 metal piece to make it flat again (from various light ridges). The other side appears to have many spin pin that I can't remove, so I didn't sand it down. Since I didn't remove the hydraulic pump actuator, my worry while doing that was contamination. So I always hold it with holes pointing down, wiped, clean carefully.
The plastic appears to be ok. I put them back, torque a bit harder. That didn't work. It's too hard to slide. So I had to lessen the bolts. At the end, it's still tighter, but not very tight.
That did reduce the "step" feedback greatly on the front dial, which is a concern for me. When I tested it with the top open, and only doing speed change, not rotating spindle, there are 4 ways that oil can spray out and can give an oil shower. Front, back, left and right. The left and right only happens exclusively, depending high or low gear selection ( I think below or above 300 rpm, not remember exactly). So that is helpful, since I can just block it up with a towel and one hand.
The front and back is not that bad, but can also be helped with a towel. But some how my memory tell me one case it did it both left right, and I put a towel on one end while block the other, but not 100% sure about this.
Another concern I have is tighten it would eventually break the round plastic part.
I also cleaned up the contacts of the 0 speed sensor. Increased the fluid pressure on the back electric panel a bit. I didn't hook up a pressure gauge to check. I think it should be between 200 and 250 psi (or 300psi?) as spec.
The lathe runs much smoother and no electrical issue. I noticed before the reason for the noise was that the lathe was stuck in the beginning running slow speed (even with high speed settings). It starts slow, growling, then kicks to higher speed and smooth.
Now, that actually also happens, but mostly gone for lower speed range. For higher speed, the slow period various, with highest 1200 rpm, it may take 2 or 3 seconds.
Can someone please tell me if this is normal? My rotary converter has somewhat balanced voltages among 3 branches, and a little off when not powering a machine (when not powering a machine, I recall it's something 122v, 132v and 138v).
Another issue I have is somehow the middle "B" selector of the thread cutting dial range is very hard to engage. The dial is broken, so maybe, just maybe it's that, but I just can't even feel anything "engaged" when I move it to the middle. After a very long time, I ended up get it to engaged and produce correct ratio.
When not engaged correctly, it either doesn't turn the screw rod, run at the higher or lower settings. When it runs, no noisy sound, so I hope that is good.
I hope there is some guide removing this assembly, since I have some oil leak on this part. My fault when I transport the late. The handle pointed down. So it was pressed against something (even when I put a 2x4 below), maybe when the 2x4 was off. But it broken. That also puts pressure on the metal shaft and damaged the seal.
Another thing I have been doing lately was getting my horizontal mill to a better condition. The left horizontal table's dial never work (it has a square end, maybe for using a wrench or connecting a power feed). I took it out and a spring pin between the shaft and the gear broken off. So I will replace it. I also found the bronze bushing wore out. I made another one for that.
The main cause (I think) was because the cast iron casing wasn't working correctly somehow. The cap wasn't in all flush. Deep inside there were some uneven surfaces and grooves. I ended up making the square shaft turn smoothly by using rotary tool to cut out those grooves, then use sand paper wrapped around a large socket to smooth the inside out (yes, very low precision, versus cutting it via a mill). It works smoothly now.
I still need to replace a broken "canvas" in the back of the Z-table protecting the chips falling down onto the screw rod. Anyone have any suggestion? I am thinking about using a piece of leather, like a cut out from an old leather couch or a welder apron. What material would best suit for this? I think it may needs to have some "folding" pattern so it can fold into a Z shape when collapsed.
Sorry for the long post, whiny post
